Device for controlling a key-operable, power-driven line spacing and carriage return

ABSTRACT

The operation of a conventional power-driven typewriter mechanism for line indexing a paper platen and moving a carriage to a left margin position is controlled by a latching arrangement which is provided for engaging and effecting the operation of a clutch in the power drive to the mechanism. The latching arrangement is initially operated by depressing a carriage return key to a first position to initiate the operation of the clutch to cause line indexing and carriage movement to a left margin position, whereupon further depression of the carriage return key causes the latching arrangement to repeatedly engage and operate the clutch for effecting repeated line indexing. When the clutch is engaged and operated by the latching arrangement to effect carriage movement, the latching arrangement is temporarily removed from the control of the carriage return key so that if power to the typewriter is interrupted the latching arrangement will be disengaged from the clutch to prevent further operation when power to the typewriter is restored. In addition, the latching arrangement may also be disengaged from the clutch to interrupt the movement of the carriage by actuating another suitable key, for example, the space bar.

United States Patent 1191 Lend] 1451 Sept. 10, 1974 [75] Inventor: Josef Lendl, Ottensoos, Germany [73] Assignee: Adlerwerke vorm Heinrich Kleyer Aktiengesellschaft, Frankfurt (Main), Germany [22] Filed: June 14, 1972 [21] App]. No.: 262,627

[30] Foreign Application Priority Data June 16, 1971' Germany 2129842 [52] [1.8. CI 197/120, 197/65, 197/66, 197/98, 192/26, 192/81 R 51 1111. c1 B41j 19/90 ['58] Field of Search 197/16, 65, 66, 67, 68, l97/120, 98; 192/81 R, 82 R, 26

[56] References Cited UNITED STATES PATENTS 1,082,063 12/1913 Ammerman 197/66 2,913,158 12/1959 192/81 R 2,157,053 5/1939 Crumrine 197/65 3,268,050 8/1966 MacFeiggan et al. 197/65 3,277,986 10/1966 ,Beare 192/26 3,393,779 7/1968 'Sacchini ..192/26 3,536,172 10/1970 Frechette 192/81 R x 3,625,332 12/1971 MCGl'ath 197/120 x 3,647,042 3/1972 Smith 197/16 x Primary Examiner-Ernest T. Wright, Jr. Attorney, Agent, or FirmJoseph R. Spalla; Keith D. Moore ABSIRACT The operation of a conventional power-driven typewriter mechanism for line indexing a paper platen and moving a carriage to a left margin position is controlled by a latching arrangement which is provided for engaging and effecting the operation of a clutch in the power drive to the mechanism. The latching arrangement is initially operated by depressing a carriage return key to a first position to initiate the operation of the clutch to cause line indexing and carriage movement to a left margin position, whereupon further depression of the carriage return key causes the latching arrangement to repeatedly engage and operate the elutch for effecting repeated line indexing. When the clutch is engaged and operated by the latching arrangement to effect carriage movement, the latching arrangement is temporarily removed from the control of the carriage return key so that if power to the typewriter is interrupted the latching arrangement will be disengaged from the clutch to prevent further operation when power to the typewriter is restored. In addition, the latching arrangement may also be disengaged from the clutch to interrupt the movement of the carriage by actuating another suitable key, for example, the space bar.

PAIENIED SEP 1 0 I974 sum 2 (IF 3 MARGI N STOP V 'IIIIIIQ DEVICE FOR CONTROLLING A KEY-OPERABLE, POWER-DRIVEN LINE SPACING AND CARRIAGE RETURN This invention relates to a typewriter or similar business machine having a key actuated and power-driven mechanism for line indexing a paper platen and moving a carriage along a printing path toward a left margin position, and more particularly to a power drive arrangement for controlling the operation of the line indexing and carriage-moving mechanism.

Typewriters and other similar business machines having a paper platen and a movable carriage and which are power driven 'by suitable means, for example an electric motor, often have a mechanism for line spacing the paper platen and moving the carriage along a printing path to a left margin position. The operation of the mechanism is typically initiated by depressing a carriage return key located on a keyboard, and the mechanism is usually operated by exerting a force on a drawband which is connected to the mechanism by winding the drawband onto a power driven reel. In such an arrangement, the initial pulling movement on the drawband serves to line space or line index the paper platen, while further continued pulling on the drawband serves to move the carriage along the printing path to the left margin position, whereupon the winding of the drawband is discontinued to stop the movement of the carriage. In addition, some prior art machines provide for the movement of the carriage to be stopped at any position along the printing path'by actuating another keyboard member, for example a space bar, to interrupt the winding of the drawband onto the power-driven reel.

To enable the line indexing and carriage return mechanism to operate without requiring the continued depression of the carriage return key, the drive mechanism for winding the drawband onto the reel is usually provided with some form of a latching mechanism to continue thewinding of the drawband after the carriage return key is released. However, a problem may sometimes result in the event that the power to the typewriter is interrupted while the carriage is being moved along the printing path to the left margin position. Such an event may occur as a result of a power failure or an accidental disconnection of the typewriter from a power source. In such a condition, the actuation of another key, for example a backspace key or a space key, may lead to the jamming of the carriage or other mechanical malfunctions when power is subsequently restored to the typewriter.

Accordingly, an object of the present invention is to provide a power drive for a line indexing and carriage return mechanism of a typewriter wherein the coupling of the power drive to the mechanism will be disconnected in the event of a power failure.

Another object of the invention is to provide a power drive for a line indexing the carriage return mechanism wherein repeated line indexing is effected at a left margin position by depressing a carriage return key to a secondary position for repeatedly coupling the power drive to the mechanism.

A further object of the invention is to provide a power drive for operating a line indexing and carriage return mechanism wherein the operation of the mechanism to move the carriage to a left margin position may be discontinued by actuating a suitable key, for examshown in FIG. 1;

FIG. 2a is a diagrammatic showing of a carriage return key illustrating the two positions to which it may be depressed;

FIG. 3 shows the latching arrangement of FIG. 2 when the carriage return key is depressed to a first position to initiate the operation of the clutch arrangement;

FIG. 4 shows the latching arrangement of FIG. 2 when the carriage return key is depressed to a second position to cause repeated operation of the clutch to effect repeated line indexing;

FIG. 5 shows the latching arrangement of FIG. 4 with the latching arrangement momentarily disconnected from the clutch during av repeated line indexing operation;

FIG. 6 is a diagrammatic view of the latching arrangement of FIG. 1 in association with a line indexing and carriage return mechanism for a carriage supported paper platen of a business machine;

FIG. 7 is a partial sectional view of the clutch shown in FIG. 1; and

FIG. 8 is a side view taken generally along the lines 8-8 in FIG. 7, of a ratchet shown in association with the clutch in FIG. I.

Referring now in detail to the figures in the drawing, there is shown a drive arrangment, generally indicated 1 l, for operating a typewriter mechanism, generally indicated 12, for line indexing or line spacing a paper platen 14 and moving a carriage 16. The mechanism 12 may be of a conventional type and is operated byv a drawband 18, which is connected to the mechanism 12 and wound onto a reel 20 with the initial winding movement serving to line index the paper platen l4, and with further continued winding movement serving to move the carriage 16 along a printing path toward a left margin position for engagement with a margin stop. The reel 20 may be driven by a suitable gear 13 'upon being coupled by means of a clutch 15 to a drive plate 17 mounted on the end of a drive shaft 19 which is rotatably driven by suitablemeans, such as a motor 32. The clutch 15 is rotatably driven along with the drive plate 17, and the operation of the clutch 15 toeffect the winding of the drawband 18 is controlled by a control member 21 in the form of a ratchet wheel. The ratchet wheel 21 rotates with the clutch 15 but is movable relative thereto with adjustable torque for initiating the operation of the clutch 15 upon being engaged and brought to a stop by means of a latch 23. The movement of the latch 23 to operate the clutch 15 may be accomplished by depressing a conventional carriage return key 25. The line indexing and carriage return mechanism 12 is shown diagrammatically by way of example only and other parts of the typewriter are not shown since they form no part of the present invention and may be desirably conventional.

When the carriage return key 25 is depressed to a first position a, as shown in FIG. 2a, to actuate the line indexing and carriage return mechanism 12, the operation of the clutch is initiated by moving the latch 23 into engagement with the ratchet wheel 21 to stop the rotational movement thereof. As shown, the carriage return key 25 is mounted on a key lever 27, which is pivotally supported about a rod 29 located in a key lever bearing 31. By depressing the carriage return key 25, the key lever 27 is pivoted about the rod 29 to press a forwardly projecting nose portion 33 of the key lever 27 against the latch 23 and push the latch 23 forwardly against the urging of a spring 35 into engagement with the ratchet wheel 21. As the latch 23 engages the ratchet wheel 21, a pawl 24 formed on the latch 23 catches one of the teeth 22 of the ratchet wheel 21 to bring the rotating ratchet wheel 21 to a stop and thus initiate the operation of the clutch 15.

The clutch 15 may be of a conventional type, similar to that disclosed in US. Pat. No. 3,268,050, with a coiled wrap spring 28 being used to couple the rotating drive plate 17 to the gear 13 for driving the reel 20. As shown in FIGS. 7 and 8, the spring 28 is coiled about adjacent hub portions 17 and 13' of the drive plate 17 and the gear 13 respectively, and the ratchet wheel 21 is rotatably carried on a sleeve 30 surrounding the portion of the spring 28 coiled about the hub portion 13 of the gear 13. One end 28' of the spring 28 is connected to the hub portion 17' while the other end 28 is connected to the sleeve 30 which carries the ratchet wheel 21 in a rotatably sliding frictional engagement with a groove 30'. Normally, the ratchet wheel 21 rotates with the sleeve 30 due to the frictional engagement which may be adjusted, as shown in FIG. 8, by twisting a threaded screw 34 securing adjacent but separated portions of the ratchet wheel 21. However, when the rotating ratchet wheel 21 is brought to a stop by engagement with the latch 23, the ratchet wheel 21 retards the rotational movement of the sleeve 30 sufficiently to constrict the spring 28 about the hub portion 13' of the gear 13, thereby driving the reel 20 to wind the drawband 18.

As more particularly shown in FIG. 1, the latch 23 is pivotally supported on a plate 37 by tabs 39, 41 which are received in slots 43, 45 respectively, which are formed in the plate 37, and the latch 23 is pivoted into engagement with the ratchet wheel 21 by the forwardly projecting nose portion 33 pressing against a small arm portion 23a of the latch 23. The arm portion 23a is engaged by the nose portion 33 over a short vertical distance indicated y above a lower edge of the arm portion 23a and which may be on the order of 1.5 mm. As the pawl 24 of the latch 23 catches a tooth 22 of the ratchet wheel 21, the latch 23 is pulled upwardly by the rotating ratchet wheel 21 for a short distance as determined by the tab 41. As shown, the tab 41 is in the shape of a hook extending below the plate 37 for a vertical distance indicated at which may be on the order of 2 mm. Since the distance x is greater than the distance y, the lower edge of the arm portion 230 of the latch 23 is pulled above the projecting nose portion 33 by the rotating ratchet wheel 21 before the rotating ratchet wheel 21 is brought to a stop by the hooked tab 41 engaging the bottom of the plate 37, thus initiating the operation of the clutch 15 while at the same time freeing the latch 23 from engagement with the nose portion 33 of the key lever 27.

Once the power drive 11 for the line indexing the carriage return mechanism 12 has been initiated, it is no longer necessary to continue to depress the carriage re turn key 25 since the latch 23 will remain engaged with the ratchet wheel 21 until the carriage 16 is brought into engagement with the margin stop 26 at the left margin position. Upon reaching the left margin position, the carriage 16, in a desirably conventional manner, effects a slight movement of the margin stop 26 so as to cause the actuation of a mechanically linked plunger, generally indicated 49, which forces the latch 23 from engagement with the ratchet wheel 21 to discontinue the winding of the reel 20 and thus stop the movement of the carriage 16. When the latch 23 is removed from the ratchet wheel 21, the ratchet wheel 21 resumes its normal rotational movement with the rotating clutch 15 while the latch 23 is returned to a rest position against an abutment 51 by means of the spring 35 which is stretched between the latch 23 and the mounting plate 37. 1f the carriage return key 25 is no longer depressed, then the latch 23 returns the distance x to engagement with the mounting plate 37. However, if the carriage return key 25 remains depressed, then the latch 23 will ride onto the projecting nose portion 33 of the key lever 27 and remain in a raised position until the carriage return key 25 is no longer depressed, whereupon the latch 23 will return to engagement with the mounting plate 37.

Since it is only necessary to disengage the latch 23 from the ratchet wheel 21 to discontinue the operation of the clutch 15, other disengaging means may be provided for moving the latch 23. As shown, a suitable connecting rod 53 may be connected to the latch 23 and be associated with another suitable key member, for example a space bar 36, so that by actuating the selected key the connecting rod 53 will be moved to pull the latch 23 from the ratchet wheel 21. Accordingly, the movements of the carriage toward the left margin may be interrupted at any position along the printing path by the actuation of a space bar 36.

From the foregoing, it can be seen that ifa power failure occurs while the power drive 11 is engaged and moving the carriage 16 toward a left margin position, then the ratchet wheel 21 will no longer hold the latch 23 in a raised position and the latch 23 will be returned to a rest position under the urging of the spring 35. As previously described, if the carriage return key 25 remains depressed then the latch 23 will ride onto the projecting nose portion 33 of the key lever 27, but if the key 25 is no longer depressed then the latch 23 will return to engagement with the mounting plate 37 With the latch 23 disengaged from the ratchet wheel 21, the reel 20 will be uncoupled by the clutch 15 and the subsequent restoration of power to the typewriter will not cause further movement of the carriage 16, thereby preventing the jamming of the typewriter carriage 16 or other mechanical malfunctions by the operation of other typewriter keys. To again initiate the movement of the carriage 16 to a left margin position, it is necessary to again actuate the carriage return key 25.

To enable the paper platen 14 to be repeatedly lineindexed when the carriage 16 has returned to a selected left margin position, the key lever 27 is provided with a finger 55 which is resiliently biased in a forward direction for repeatedly pressing the latch 23 into engagement with the ratchet wheel 21 upon further depression of the carriage return key to a b position indicated in FIG. 2a. As more particularly shown in FIGS. 4 and 5, the finger 55 is pivotally supported on the end of the key lever 27 and resiliently biased toward the latch 23 by a spring 57 which is stretched be tween the end of the key lever 27 and an opposite end of the finger 55. The finger 55 is normally held out of contact with the latch 23 when the key lever 27 is depressed to the a position by a turned-over ear 59 on the finger 55 which contacts the key lever 27 to establish a normal position.

When the carriage 16 has returned to a left margin position in engagement with the margin stop 26 and the latch 23 has been pushed from engagement with the ratchet wheel 21 by the plunger 49, as previously described, the carriage return key 25 may be further depressed to the b position, whereupon the finger 55 presses the latch 23 back into engagement wtih the ratchet wheel 21 so as to again initiate the power drive mechanism 11 to cause a further line indexing of the paper platen l4 and movement of the carriage 16. After line indexing the paper platen 14 the carriage 16 will begin to move, however since it is already engaging the margin stop 26 at the left margin position the plunger 49 is again actuated to push the latch 23 from the ratchet wheel 21 to the rest position abutting the stop 51. As the plunger 49 is retracted, the finger 55 is again urged by the spring 57 to return 21, and latch 23 into engagement with the ratchet wheel 2l,and this operation continues so long as the carriage return key 25 remains depressed to the b position.

While only a single embodiment of the present invention has been illustrated and described, it will be apparent to those skilled in the art that various modifications and improvements may be made without departing from the scope and spirit of the invention. Accordingly, it is to be understood that the invention is not to be limited by the illustrative embodiment, but only by the scope of the depending claims.

What is claimed is: v

1. ln a business machine having a mechanism for line indexing a paper platen and moving a carriage along a path to a left margin position, and a rotatable power drive for operating the mechanism, the combination comprising:

clutch means connected to said rotatable power drive for rotational movement therewith and being operable for coupling said mechanism to said rotatable power drive,

said clutch means having a control member normally driven in rotation therewith and supported for movement relative thereto for coupling said clutch means to said mechanism,

latch means supported for movement into engagement with said control member to effect relative movement thereof for coupling said clutch means to said mechanism,

resilient biasing means urging said latch means from said control member to an inoperative position,

a key lever having a projecting nose for engaging a portion of said latch means and being movable in one direction for moving said latch means against the urging of said resilient biasing means into engagement with said control member to effect relative movement thereof for coupling said clutch means to said mechanism, and

said latch means being movably driven by said control member against the urging of said resilient biasing means for disengaging said portion thereof from said projecting nose and enabling said latch means to be returned to the inoperative position upon discontinuance of therotational movement of said clutch means and said rotatable power drive.

2. In a business machine according to claim 1, the

combination further comprising:

a disengaging member associated with a margin stop at the left margin position and operable in response to the movement of the carriage to the left margin position for disengaging said latch means from said control member to effect uncoupling of said clutch means from said mechanism,

said key lever being further movable in said one direction upon movement of said latch means by said rotating control member,

a pressure member movably supported on said key lever for engaging said latch means upon further movement of said key lever in said one direction,

another resilient biasing means urging said pressure member in a direction to press said latch means into engagement with said control member to effect relative movement thereof for coupling said clutch means to said mechanism, and

said disengaging member being operable in response to the coupling of said clutch means to said mechanism at the left margin position for disengaging said latch means from said control member against the urging of said other resilient biasing means to effect uncoupling of said clutch means from said mechanism at the left margin position.

3. In a business machine according to claim 1, the

combination further comprising:

a connecting member connected to said latch means and associated with a key member,

said connecting member being movable in response to the actuation of the key member when the carriage is at any position along the path for disengaging said latch means for said control member to effect uncoupling of said clutch means from said mechanism to stop the movement of the carriage along the path.

4. In a business machine according to claim 2, the

combination further comprising:

a disconnecting member connected to said latch means and associated with a key member,

said disconnecting member being 'movable in response to the actuation of the key member when the carriage is at any position along the path for disengaging said latch means from said control member to effect uncoupling of said clutch means from said mechanism to stop the movement of the carriage along the path. 

1. In a business machine having a mechanism for line indexing a paper platen and moving a carriage along a path to a left margin position, and a rotatable power drive for operating the mechanism, the combination comprising: clutch means connected to said rotatable power drive for rotational movement therewith and being operable for coupling said mechanism to said rotatable power drive, said clutch means having a control member normally driven in rotation therewith and supported for movement relative thereto for coupling said clutch means to said mechanism, latch means supported for movement into engagement with said control member to effect relative movement thereof for coupling said clutch means to said mechanism, resilient biasing means urging said latch means from said control member to an inoperative position, a key lever having a projecting nose for engaging a portion of said latch means and being movable in one direction for moving said latch means against the urging of said resilient biasing means into engagement with said control member to effect relative movement thereof for coupling said clutch means to said mechanism, and said latch means being movably driven by said control member against the urging of said resilient biasing means for disengaging said portion thereof from said projecting nose and enabling said latch means to be returned to the inoperative position upon discontinuance of therotational movement of said clutch means and said rotatable power drive.
 2. In a business machine according to claim 1, the combination further comprising: a disengaging member associated with a margin stop at the left margin position and operable in response to the movement of the carriage to the left margin position for disengaging said latch means from said control member to effect uncoupling of said clutch means from said mechanism, said key lever being further movable in said one direction upon movement of said latch means by said rotating control member, a pressure member movably supported on said key lever for engaging said latch means upon further movement of said key lever in said one direction, another resilient biasing means urging said pressure member in a direction to press said latch means into engagement with said control member to effect relative movement thereof for coupling said clutch means to said mechanism, and said disengaging member being operable in response to the coupling of said clutch means to said mechanism at the left margin position for disengaging said latch means from said control member against the urging of said other resilient biasing means to effect uncoupling of said clutch means from said mechanism at the left margin position.
 3. In a business machine according to claim 1, the combination further comprising: a connecting member connected to said latch means and associated with a key member, said connecting member being movable in response to the actuation of the key member when the carriage is at any position along the path for disengaging said latch means for said control member to effect uncoupling of said clutch means from said mechanism to stop the movement of the carriage along the path.
 4. In a business machine according to claim 2, the combination further comprising: a disconnecting member connected to said latch means and associated with a key member, said disconnecting member being movable in response to the actuation of the key member when the carriage is at any position along the path for disengaging said latch means from said control member to effect uncoupling of said clutch means from said mechanism to stop the movement of the carriage along the path. 